Thread measuring and locking device for sewing machines



June 17, 1941. F. A. LARSON 2,245,796.

THREAD MEASURING AND LOCKING DEVICE FOR SEWING MACHINES Original Filed Jan. l8, 1936 2 Sheets-Sheet A v B ATTORNEY June 17, 1941. F. A. LARSON 4 ,7 THREAD MEASURING AND LOCKING DEVICE FOR SEWING MACHINES Original Filed Jan. 18, 1936 2 Sheets-Sheet 2 FHA lV/rA 4 A9504; W cw 41mm! Patented June 17, 1941 THREAD MEASURING AND LOCKING DEVICE FOR SEWING MACHINES Frank A. Larson, Saugus, Mass.

Original application January 18, 1936, Serial No. 59,723. Divided and this application March 8, 1938, Serial No. 194,655

6 Claims. (01. 112-58) This invention relates to a device for automatically measuring out thread in a sewing machine according to the thickness of the material being sewn, and automatically locking the thread to prevent drawing more than is measured, and while having other and more general fields of usefulness, is particularly suited for use with shoe sewing machines adapted to stitch through the outer sole of the shoe. The subject matter of the invention constitutes a division from. my prior application, S. N. 59,723, now Patent No. 2,110,650, patented March 8, 1938. A principal object of the invention is to provide simple, reliable means connected with, and controlled by, the presser foot of the machine adapted to feed out and supply to the needle between stitches, predetermined amounts of thread that are varied and controlled as to amount by the extent that the presser foot opens to receive different thicknesses of work. The foregoing and other objects and advantages of the invention will be better understood from the following detailed descrip-, tion taken in connection with the accompanying drawings, and the distinctive features of novelty will be thereafter pointed out in the appended claims.

Referring to the drawings:

Figure 1 is a side view showing the operative connections and instrumentalities of the sewing machine with which the present invention is concerned; a I

Figure 2 is a fragmentary view on a relatively larger scale showing the immediate thread measuring instrumentality in position ready ,for

measuring; I

Figure 3 is a diagrammatic sideelevation of the operative elements during the operation of measuring the thread; i

Figure 4 is a view similar to Figure 2, but showing the disposition of the threadafter being measured, and;

Figure 5 is a fragmentary side view showing the presser foot of themachine and its operative connection with the thread measuring instrumentality.

Since the device of the present invention is shown as applied to a sewing machine of the type disclosed in my said prior patent, references are made to said patent for further and complete disclosure of all cooperative parts of the machine not fully disclosed herein.

It! indicates the immediate thread measuring instrumentality comprising an arm pivoted at one end to the machine framework on a stud I I. The thread T supplied from a spool (not shown) passes downward through an opening I2 toward the free end of. this arm and then upward through another opening I3 spaced asmall distance forward thereof, then under a leaf spring I4 secured to the arm I!l,,then downward through another opening I5 in the extremity of the arm, and then after passing through the wax pot it is directed around take up rollers Iii, H, to the needle. A tension spring I8 acts on the arm III to normally draw it downward so that it engages a pin I9 located between the openings I2, I3 in position to clamp the thread against the bottom of the arm' II] when it is pressed thereagainst. The pin I9 is provided with a hook or eye I9a through which the thread passes freely. It will thus be noted that upon a lifting movement imparted to the arm I6, it is instantly disengaged from the pin I9 so that the thread may be drawn through i said arm as it raises with only the light frictional resistance imposed by the spring I4. For thus lifting the arm I0 it has an adjustable depending element shown as a screw 20 engaged by an arm 2 Ia of a bell crank lever 2|, which is connected for operation through a link system 22 from the main shaft 23 of the machine, the same as in my said prior patent. The adjustment of the screw 20 thus provides means for determining generally the amount of thread measured out at each movement of the arm I0, since the arm ID will be' moved to a greater or less extent by the arm 2 I a according to the nearness thereto, of the screw 20 when the arm 2Ia begins its upward movement. In accordance with my invention, means is provided whereby the amount of thread measured out is reliably and closely regulated and varied according to the extent that the presser foot 24 is held open by the work. For this purpose, the pin I 9 is borne at the free end of an arm 25 fixed to a pin 26 journaled in the machine framework and having fixed therewith, a block 21. The block 21 is adjustable in a fork 28 of an arm 29 and thus an oscillation of arm 29 effects a like oscillation of the pin 26 and of the arm. 25. The free end of thearm 29 has a pin and slot engagement 3|] with the arm 3I which bears the presser foot 24, this arm being pivoted to the machine frame at 32, and having an operative connection thereto, at 3Ia for intermittently opening the presser foot, such connection not being shown herein, but fully shown and disclosed in my said patent. The arm 29 is equipped with an upwardly extending pin or rod 33, which is engaged by a tension spring 34 which thus tends constantly to move the presser foot 24 downward into engagement with the work, and at the same time through the described connections to move the pin [9. It thus results that the farther down the presser foot 24 may so move to engage the work, i. e., the thinner the work piece, the farther upward the arm it! will be held by the pin H3, at the beginning of a thread measuring movement, and hence said arm will be moved to a correspondingly less extent to measure out less thread as the work piece is thinner, and in like manner it will be moved farther by the engagement of the arm Zia therewith, to measure out more thread as the work piece is thicker. Itwill-be understood that during this thread measuring; operation, the take-up rollers l6, H, are held in take-up position by the linkage connections I611, Ha, the same as in my said-patent, and that upon the completion of the thread measuring movement, and when the arm I again moves downward and engages the pin is, the take-up rollers l5, H, are moved through the described connections to reiease the measured out thread to the needle. It will be understood: that in the thread measuring out movement, the thread being held yieldingly by the spring M will be drawn through the eye or hook Mia and rest loosely adjacent'such hook ready to be drawn past the light resistance of the spring M for use. At this time it will be noted that arm It has returned to rest against pin is looking the thread tightly between'these two parts and also that as the measured amount of thread is drawn taut in making the stitch that the path of the thread up and down through the end of arm ll is such that the harder the pull on the'thread, the greater the pressure exerted by arm H] against the thread resting on pin l5, thus always tending to lock the thread more securely and positively.

I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to beconsidered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

Having now described my invention, what I claimas new and desire to secure by Letters Pate ent is:

1. The combination with a sewing machine,- of means for measuring out predetermined and variable amounts of thread to the needle thereof, comprising an oscillating thread measuring memher through which the thread is threaded, said member arranged for engagement and actuation by a member of the machine having a predetermined range of movement, a stop engageable by said thread measuring member, and connected to be automatically varied in position according to the setting of the presser footof the machine, from which stop said thread measuring member is pressed by said movable memberof the machine, and a spring acting to draw said thread measuring member and hold it against said stop, whereby the thread measured out by said member varies according to the extent of opening of the presser foot, the threading arrangement through said thread measuring member being such with respect to said stop that the stop engages the thread and clamps it against said thread-measuring member as said member engages said stop.

2. Apparatus as set forth in claim 1 wherein the thread measuring member is equipped with a spring member yieldingly engaging the thread to exert tension thereon.

3. Apparatus as set forth in claim 1 wherein the presser foot is borne by an oscillating arm, and another oscillating arm is provided with pin and slot connection to the presser foot arm, the second named arm equipped with connections including said stop adapted to engage said thread measuring member at different points according to the setting of the presser foot, so that said thread measuring member is acted on to a greater or less'extent by said movable machine member to vary the extent of thread measured out.

4. The combination with a sewing machine, of a presser foot to engag the material, a thread measuring device having a separate take-up de vice associated therewith, means for operating said take-up device in timed relation to the operation of the machine, and connections from the presser foot to the thread measuring device whereby the amount of thread measured out is varied automatically according to the extent of opening of the presser foot as it engages the Work, the thread measuring device including a member movable for drawing off a given amount of thread, and a member included in said connections operatively connected Withthe presser foot and movable into engagement with the first named member for locking the thread therebetween at the completion of a thread measuring movement.

5. Apparatus as set forth in claim 4 wherein two members comprising the thread measuring device are cooperatively arranged and mounted to turn respectively on spaced apart axes, the arrangement being'such that the thread is looked after a measuring movement more strongly and positively, according to the degree ofpull exerted thereon.

6. Apparatus as set forth in claim 4 wherein two members comprising the thread measuring device are mounted to turn respectively on spaced apart axes, through one of which membersthe thread is threaded with the otherof said members adapted to clamp and lock the thread more strongly according to the degree of pull exerted thereon.

FRANK: A. LARSON. 

